Further purification and rigorous characterization of normal human brain sphingomyelinase will continue. A major focus would be to characterize the molecular differences of sphingomyelinase A and B, because this could shed light on the enzymatic differences of the neuropathic and non-neuropathic forms of Niemann-Pick disease. Detailed studies of very long chain fatty acid metabolism in fibroblasts from patients with adrenoleukodystrophy will be attempted using (1-14C)cerotic acid. Possible genetic interrelationship between galactosylceramidase and GM1-ganglioside beta-galactosidase will be approached at the most fundamental level, purification of both enzymes and rigorous chemical characterization.